1. Field of the Invention
The present invention relates to a method of driving a servo motor with a built-in drive circuit. In particular, the present invention relates to a novel improvement of a servo motor for attaining a reduction in size, thereby facilitating additional installation of the servo motors. The reduction in size of the servo motor can be attained by using: a plurality of the servo motors each having a built-in drive circuit; and a distribution board for distributing DC power and a communication signal to be supplied to each of the servo motors, and by providing a rectifying circuit common to the respective motors to the distribution board.
2. Description of the Related Art
Hitherto, there is known a motor encoder using an encoder as a conventional servo motor of this type (see, for example, JP 62-278408 A).
In the above-mentioned motor encoder, a motor and an encoder are combined into an integral unit, which is servo-driven by an external drive signal.
The conventional servo motor is constructed as described above, and therefore has the following problems.
That is, the servo motor contains the encoder alone, and the driver system, (that is, the drive circuit) is provided outside the motor as a separate component. Accordingly, when a number of servo motors are used as a multi-axis system, as in the case of a machine tool or a robot, the space occupied by the respective drive circuits of the motors constitutes an obstruction, making it difficult to achieve a reduction in size. Apart from the above, there has also been proposed a construction in which-part of the drive circuits arranged inside the motor. However, a construction containing a rectifier for AC/DC conversion and a capacitor leads to an increase in overall size, which is incompatible with the demand for a reduction in size.